With the development of technologies, a servo motor plays an important role in both the conventional industries and the high-end technology industries. It is also an inevitable trend to fabricate the servo motor with a smaller volume, greater power and a lower cost. Currently, a high torque servo motor is more and more widely applied in a processing apparatus, and thus the demands for the high torque servo motor are increased. The most outstanding advantage of the high torque servo motor is that it does not need a decelerator to increase the torque output, thereby saving the cost of disposing the decelerator and reducing the volume of the apparatus.
The output torque of the motor is closely associated with the input current, and larger current needs to be input in order to output a higher torque. However, when large current is input into the motor, the heat dissipation problem needs to be considered. When the input current is increased, the heat generated by the motor winding is also increased accordingly, and thus the temperature of the motor is significantly increased. If the motor is installed on the processing apparatus, the temperature of the motor may affect the workpiece and cause thermal deformation of the workpiece. Therefore, a heat dissipation system is further added to the motor system and is adapted for controlling the temperature of the motor.
Currently, the heat dissipation system adopted by the servo motor is an externally connected cooling water passage, and the heat, generated by the motor, is removed by a cooling fluid in the cooling water passage. However, in the above heat dissipation manner, only after the temperature inside the motor rises, the heat generated by the motor is transferred to the cooling water passage through the thermal conduction, of the material, of the motor, and is then dissipated by the cooling fluid. Furthermore, in the current heat dissipation manner, the cooling fluid can only dissipate a large amount of heat after a temperature difference between the motor and the cooling water passage reaches a certain level. Therefore, if the temperature inside the motor rises dramatically, the cooling water passage cannot dissipate the heat, through heat transfer, in time, so that the temperature inside the motor is rather high and exceeds what can be endured by the material of the motor, thus causing damages to the motor.